Method for manipulating a tissue structure within a thoracic cavity

ABSTRACT

A method for manipulating a tissue structure within a body cavity provides for retracting and supporting the heart wall to provide access into the heart during a cardiac surgical procedure. In one embodiment of the present invention, a surgical tool support apparatus comprises a base having an atraumatic tissue-engaging surface and an aperture for receiving an elongate tool. The apparatus also has a clamp assembly aligned with the aperture and spaced-apart from a surface of the base opposite to the tissue-engaging surface. The apparatus is particularly useful in maintaining a retracting force on a surgical tool used to manipulate tissue within a body cavity such as the thoracic cavity.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of commonly-assigned,co-pending application Ser. No. 08/577,547, filed Dec. 22, 1995 which isa divisional of 08/294,454, filed Aug. 23, 1994, now U.S. Pat. No.5,613,937, which is a continuation-in-part of application Ser. No.08/163,241, filed Dec. 6, 1993 now U.S. Pat. No. 5,571,215, which is acontinuation-in-part of application Ser. No. 08/023,778, filed Feb. 22,1993 now U.S. Pat. No. 5,452,733. The complete disclosures of theseapplications and patents are hereby incorporated herein by reference.

BACKGROUND OF THE INVENTION

This invention relates generally to instruments and techniques forperforming less-invasive surgical procedures, and more specifically, toless-invasive instruments and techniques for retracting tissuestructures within body cavities such as the abdomen or thorax.

Various types of surgical procedures are currently performed toinvestigate, diagnose, and treat diseases of the heart and the greatvessels of the thorax. Such procedures include repair and replacement ofmitral, aortic, and other heart valves, repair of atrial and ventricularseptal defects, pulmonary thrombectomy, treatment of aneurysms,electrophysiological mapping and ablation of the myocardium, and otherprocedures in which interventional devices are introduced into theinterior of the heart or a great vessel.

Using current techniques, many of these procedures require a grossthoracotomy, usually in the form of a median sternotomy, to gain accessinto the patient's thoracic cavity. A saw or other cutting instrument isused to cut the sternum longitudinally, allowing two opposing halves ofthe anterior or ventral portion of the rib cage to be spread apart. Alarge opening into the thoracic cavity is thus created, through whichthe surgical team may directly visualize and operate upon the heart andother thoracic contents.

Surgical intervention within the heart generally requires isolation ofthe heart and coronary blood vessels from the remainder of the arterialsystem, and arrest of cardiac function. Usually, the heart is isolatedfrom the arterial system by introducing an external aortic cross-clampthrough a sternotomy and applying it to the aorta between thebrachiocephalic artery and the coronary ostia. Cardioplegic fluid isthen injected into the coronary arteries, either directly into thecoronary ostia or through a puncture in the aortic root, so as to arrestcardiac function. In some cases, cardioplegic fluid is injected into thecoronary sinus for retrograde perfusion of the myocardium. The patientis placed on cardiopulmonary bypass to maintain peripheral circulationof oxygenated blood.

Of particular interest to the present invention are intracardiacprocedures for surgical treatment of heart valves, especially the mitraland aortic valves. According to recent estimates, more than 79,000patients are diagnosed with aortic and mitral valve disease in U.S.hospitals each year. More than 49,000 mitral valve or aortic valvereplacement procedures are performed annually in the U.S., along with asignificant number of heart valve repair procedures.

Various surgical techniques may be used to repair a diseased or damagedvalve, including annuloplasty (contracting the valve annulus),quadrangular resection (narrowing the valve leaflets), commissurotomy(cutting the valve commissures to separate the valve leaflets),shortening mitral or tricuspid valve chordae tendonae, reattachment ofsevered mitral or tricuspid valve chordae tendonae or papillary muscletissue, and decalcification of valve and annulus tissue. Alternatively,the valve may be replaced, by excising the valve leaflets of the naturalvalve, and securing a replacement valve in the valve position, usuallyby suturing the replacement valve to the natural valve annulus. Varioustypes of replacement valves are in current use, including mechanical andbiological prostheses, homografts, and allografts, as described inBodnar and Frater, Replacement Cardiac Valves 1-357 (1991), which isincorporated herein by reference. A comprehensive discussion of heartvalve diseases and the surgical treatment thereof is found in Kirklinand Barratt-Boyes, Cardiac Surgery 323-459 (1986), the completedisclosure of which is incorporated herein by reference.

The mitral valve, located between the left atrium and left ventricle ofthe heart, is most easily reached through the wall of the left atrium,which normally resides on the posterior side of the heart, opposite theside of the heart that is exposed by a median sternotomy. Therefore, toaccess the mitral valve via a sternotomy, the heart is rotated to bringthe left atrium into an anterior position accessible through thesternotomy. An opening, or atriotomy, is then made in the right side ofthe left atrium, anterior to the right pulmonary veins. The atriotomy isretracted by means of sutures or retraction devices, exposing the mitralvalve directly posterior to the atriotomy. One of the aforementionedtechniques may then be used to repair or replace the valve.

An alternative technique for mitral valve access may be used when amedian sternotomy and/or rotational manipulation of the heart areundesirable. In this technique, a large incision is made in the rightlateral side of the chest, usually in the region of the fourthintercostal space. One or more ribs may be removed from the patient, andother ribs near the incision are retracted outward to create a largeopening into the thoracic cavity. The left atrium is then exposed on theposterior side of the heart, and an atriotomy is formed in the wall ofthe left atrium, through which the mitral valve may be accessed forrepair or replacement.

Using such open-chest techniques, the large opening provided by a mediansternotomy or right thoracotomy enables the surgeon to see the mitralvalve directly through the left atriotomy, and to position his or herhands within the thoracic cavity in close proximity to the exterior ofthe heart for manipulation of surgical instruments, removal of excisedtissue, and/or introduction of a replacement valve through the atriotomyfor attachment within the heart. However, these invasive, open-chestprocedures produce a high degree of trauma, a significant risk ofcomplications, an extended hospital stay, and a painful recovery periodfor the patient. Moreover, while heart valve surgery produces beneficialresults for many patients, numerous others who might benefit from suchsurgery are unable or unwilling to undergo the trauma and risks ofcurrent techniques.

In response to the various problems associated with open-chestprocedures, new methods of performing closed-chest surgery on the heartusing minimally invasive thoracoscopic techniques have been recentlydeveloped. In these methods, the patient's heart is arrested byoccluding the patient's aorta between the coronary arteries and thebrachiocephalic artery with an expandable balloon on the distal end ofan endovascular catheter introduced via a femoral artery. Cardioplegicfluid is then delivered to the patient's myocardium through a lumen inthe same catheter or through a catheter positioned in the coronary sinusvia a peripheral vein. To repair or replace the mitral valve,minimally-invasive cutting and suturing instruments are then introducedthoracoscopically through a trocar sleeve in the right lateral portionof the chest. A complete description of such methods is found incommonly assigned, co-pending application Ser. No. 08/163,241, filedDec. 6, 1993, now U.S. Pat. No. 5,571,215 which has been previouslyincorporated herein by reference.

This new generation of thoracoscopic methods of performing heart valverepair has, of course, created many new challenges. One such challengeis that of retracting the left atrial wall to open the atriotomy so thatthe mitral valve can be exposed for the surgical procedure. The heartwall must be retracted anteriorly to suitably expose the mitral valveand provide access through the atriotomy for the cutting and suturinginstruments introduced through the right lateral portion of the chest.In addition, the instruments that retract the heart wall must beintroduced in a minimally-invasive manner through small percutaneousincisions or cannulae positioned in intercostal spaces in the patient'srib cage.

Introducing an instrument through an intercostal space in the anteriorside of the chest presents additional problems. One such problem is thatthe patient's rib cage is typically structured so that the ribs in theanterior portion of the chest are closer together than in the lateralportions of the chest. In addition, the tissue layer in the anteriorchest wall contains nerves that could be damaged by a large percutaneousincision. Therefore, a retraction device introduced from the anteriorside should be as small as possible, preferably on the order of 3-8 mm,to fit within the smaller anterior intercostal spaces and to avoidunnecessary trauma to the patient. Another problem is that the part ofthe retraction device that engages the heart wall must be wide enough toengage a sufficient portion of the heart wall to open the atriotomyenough to expose the mitral valve. It must also be long enough to extenda sufficient distance into the heart to extend beneath the interatrialseptum and prevent it from sagging or otherwise inhibiting access to themitral valve. Introducing an instrument which is large enough tosufficiently expose the mitral valve through the smaller intercostalspaces in the anterior portion of the chest is problematic.

Additionally, portions of the heart wall are typically retracted for asubstantial period of time during the mitral valve replacementprocedure. Conventionally, retraction is maintained by a nurse orsurgeon physically holding a retractor in position for the duration oftime required. Alternatively, some surgeons have jerry-rigged scissorclamps or other devices to hold the retractor in position duringsurgery. The first approach is an inefficient use of resources, and thesecond creates a dangerous situation should one of the jury-riggedclamps fail. These approaches also fail to provide a reliable andconsistently stable retraction of heart tissue as required during suchdelicate interventional procedures. Although some large, floor-basedpositioning devices exist that have an arm extending from the floor upand over the patient, they fail to provide the ease of removal andcompact configuration required in the close quarters of the operatingarea. The larger devices tend to retract laterally when the devicecannot be positioned directly over the site of retraction and aredifficult to remove if fluoroscopy or other diagnostic procedures needto be performed during the course of valve replacement.

What is needed, therefore, are improved apparatus, systems, and methodsfor manipulating a tissue structure in a body cavity via a smallpercutaneous penetration or cannula. Particularly, the apparatus,systems, and methods should be capable of providing constant andreliable retraction of tissue in the thoracic cavity during delicate andsensitive procedures such as mitral valve replacement. The apparatuswould preferably be of compact design, being easily deployable,adjustable, and removable from the patient, while providing constant,reliable retraction without requiring the services of a nurse or doctorto maintain retracting force.

SUMMARY OF THE INVENTION

The present invention provides apparatus, systems, and methods formanipulating a tissue structure in a body cavity through a smallpercutaneous penetration in a patient. The system is preferablyconfigured for use with a small percutaneous penetration into a bodycavity and for retracting an incision in the left atrium from theanterior side of the chest. The system is well suited for providingconstant and reliable retraction of the heart wall, making the inventionparticularly useful during surgeries such as mitral valve replacement.While being especially useful for thoracoscopy, the present invention isalso useful in other surgical procedures, such as laparoscopy andpelviscopy.

According to the present invention, a method for manipulating tissuestructure within the thoracic cavity of a patient comprises the step ofintroducing a tissue positioning tool having a shaft into the thoraciccavity through a percutaneous penetration. A force is applied to theshaft to engage the tissue structure with the tissue positioning tool,so as to reposition the tissue structure within the thoracic cavity. Atool support apparatus is positioned on an outer surface of the thoraciccavity. The positioning of the tool support apparatus may occur prior toor after the introduction of the tool into the cavity. With the desiredforce applied to the shaft, the shaft of the tissue positioning tool isfixedly secured to the support apparatus. The force to the shaft ismaintained against the repositioned tissue structure through contact ofthe tool support apparatus against an outer surface of the thoraciccavity.

In one embodiment of the present invention, the method comprises apositioning step where a base of the support apparatus is restedtangentially on the outer surface of the thoracic cavity. To facilitateengagement of the apparatus with the shaft of the positioning tool, aclamp assembly of the support apparatus is aligned with a longitudinalaxis of the shaft. The base is preferably positioned so that an aperturein the base rests directly over the percutaneous penetration. Thisallows the support apparatus to provide retraction in a direction normalto the outer surface of the cavity. It should be understood, however,that the support apparatus can provide retraction at a variety ofdifferent angles and is not limited to retraction at anglesperpendicular to the surface of the cavity.

In another embodiment of the present invention, the introduction step ofthe method comprises introducing a tissue supporting member having acontact surface into the thoracic cavity through a first percutaneouspenetration. The shaft of the tool, having a longitudinal axis, isintroduced through a second percutaneous penetration. The tissuesupporting member is connected to the shaft within the thoracic cavityto form a tissue positioning tool. Assembling the tool within thethoracic cavity allows the use of positioning devices having parts andsurfaces too large to be introduced through the typically smallerpenetration from which the shaft of the tool extends.

According to the present invention, a surgical tool support apparatuscomprises a base having an atraumatic tissue-engaging surface and anaperture for receiving an elongate tool. The apparatus also has a clampassembly aligned with the aperture and spaced-apart from a surface ofthe base opposite to the tissue-engaging surface.

In one embodiment of the invention, the apparatus comprises a basehaving a rigid plate and a biocompatible elastomeric cushion over theatraumatic surface for minimizing pressure trauma to the patient. Thecushion may be removably attached to the rigid plate. Having the cushionand other parts of the invention removable from each other facilitatescleaning and replacement of the parts of the apparatus.

In another embodiment of the invention, the clamp assembly of theapparatus is rotatably attached to the base about an axis generallyparallel to the atraumatic tissue-engaging surface. The clamp assemblytypically comprises a pair of jaws where at least one of the jaws has aflange extending from a surface of the jaw to facilitate alignment whenthe jaws close. The clamp assembly also has a closing mechanism forbring the pair of jaws into contact.

According to the present invention, a system for manipulating tissuestructure within the thoracic cavity comprises a linking member, a firstclamp, and a second clamp. The first clamp has a first jaw and a secondjaw where the first jaw is movably coupled to the second jaw by thelinking member. The second clamp is mounted on the second jaw of thefirst clamp for fixedly engaging the linking member. The second clamp ispreferably has a rotational linkage for rotatably coupling the secondjaw to the linking member.

In a further aspect of the present invention, a kit of the presentinvention comprises a base having an atraumatic tissue-engaging surfaceand an aperture for receiving an elongate tool. The kit also has a clampassembly aligned with the aperture and spaced-apart from a surface ofthe base opposite to the tissue-engaging surface. Instructions for usesetting forth a method of the present invention are enclosed in apackage along with the base and the clamp assembly. A retractor ortissue positioning tool may also be included in the package.

It should be understood that while the invention is described in thecontext of thoracoscopic surgery on the left atrium and mitral valve,the systems and methods disclosed herein are equally useful on othertypes of tissue structures and in other types of surgery, such aslaparoscopy and pelviscopy.

A further understanding of the nature and advantages of the inventionmay be realized by reference to the remaining portions of thespecification and the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a closed-chest mitral valve replacementusing minimally invasive techniques and a retractor;

FIG. 2 is a front view of the procedure of FIG. 1, showing thepositioning of the surgical instruments in the patient's chest;

FIG. 3 is a front view of a patient's cardiovascular system illustratingthe positioning of a system for arresting the heart and establishingcardiopulmonary bypass in accordance with closed-chest mitral valvereplacement;

FIG. 4A is a top view looking into the patient's thoracic cavity througha passage of an access cannula in the system of FIG. 1, showing thecreation of an atriotomy in the patient's left atrium;

FIG. 4B is a transverse cross-sectional view of the patient of FIG. 1taken through the patient's thorax, showing the introduction of thereplacement valve into the left atrium and the tying of knots in thesutures to secure a prosthesis in the patient's heart;

FIG. 5A is a perspective view of the support apparatus constructed inaccordance with the principals of the present invention;

FIG. 5B is a perspective view of the cushion of the apparatus of FIG.5A;

FIG. 5C is a perspective view of the base and L-shaped arm of theapparatus of FIG. 5A;

FIGS. 6A-6C are overhead perspective views of the apparatus of FIG. 5Afitted with a variety of clamp assembly closure devices;

FIGS. 6D-6E are perspective views of the jaws used in the clamp assemblyof the apparatus of FIG. 5A;

FIG. 7A is a perspective view of the system of the present invention;

FIG. 7B is cross-sectional view of a portion of the thoracic cavity witha retractor of the system of FIG. 7A exiting the cavity at anon-perpendicular angle and coupled to the support apparatus of thesystem;

FIGS. 8-9 is a transverse cross-sectional view of the patient of FIG. 1taken through the patient's thorax, showing the assembly of a retractoror tissue positioning tool and the use of the tool with a tool supportapparatus;

FIG. 10 is a perspective view of a closed-chest mitral valve replacementusing minimally invasive techniques, a retractor, and a tool supportapparatus of the present invention;

FIGS. 11A-11B are perspective views of alternate embodiments of a toolsupport apparatus of the present invention; and

FIG. 12 shows a kit of the present invention containing a tissuepositioning tool, a tool support apparatus of the present invention, andinstructions for use in accordance with a method of the presentinvention.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

I. Introduction

The invention provides methods and devices for facilitating surgicalinterventions within body cavities such as the thoracic cavity. Whilethe specific embodiments of the invention described herein will refer tomitral valve repair and replacement, it should be understood that theinvention will be useful in performing retraction for a great variety ofsurgical procedures, including repair and replacement of aortic,tricuspid, or pulmonary valves, repair of atrial and ventricular septaldefects, pulmonary thrombectomy, removal of atrial myxoma, patentforamen ovale closure, treatment of aneurysms, electrophysiologicalmapping and ablation of the myocardium, myocardial drilling, coronaryartery bypass grafting, angioplasty, atherectomy, correction ofcongenital defects, and other procedures in which interventional devicesare introduced into the interior of body cavities such as the thoraciccavity.

The present invention is of particular use in minimally invasiveprocedures performed in the chest through percutaneous intercostalpenetrations. The terms "percutaneous intercostal penetration" and"intercostal penetration" as used herein refer to a penetration, in theform or a small cut, incision, hole, cannula, trocar sleeve, or thelike, through the chest wall between two adjacent ribs, wherein thepatient's rib cage and sternum remain substantially intact, withoutcutting, removing, or significantly displacing the ribs or sternum.These terms are intended to distinguish a gross thoracotomy such as amedian sternotomy, wherein the sternum and/or one or more ribs are cutor removed from the rib cage, or one or more ribs are retractedsignificantly, to create a large opening into the thoracic cavity. A"percutaneous intercostal penetration" may abut or overlap the adjacentribs between which it is formed, but the maximum width of thepenetration which is available for introduction of instruments,prostheses and the like into the thoracic cavity will be the width ofthe intercostal space, bounded by two adjacent ribs in their natural,substantially undeflected positions. It should be understood that one ormore ribs may be retracted or deflected a small amount without departingfrom the scope of the invention; however, the invention specificallyseeks to avoid the pain, trauma, and complications which result from thelarge deflection or cutting of the ribs in conventional, open-chesttechniques.

Advantageously, the present invention facilitates the performance ofprocedures using percutaneous penetrations within intercostal spaces ofthe rib cage to obviate the need for a median sternotomy or other formof gross thoracotomy. The present invention is of particular use inclosed-chest mitral valve replacement.

II. Overview of a Closed-Chest Mitral Valve Replacement

A method for performing closed-chest mitral valve replacement will bedescribed with reference to FIGS. 1-10. FIG. 1 illustrates a system 20for closed-chest valve replacement positioned in a patient P on anoperating table T. Preferably, a wedge or block W having a top surfaceangled at approximately 20° to 45° is positioned under the right side ofpatient P so that the right side of the patient's body is somewhathigher than the left side. The patient's right arm A is allowed torotate downward to rest on table T, exposing the right lateral side ofthe patient's chest.

The valve replacement system 20 includes an access cannula 22 positionedpercutaneously within an intercostal space between two ribs (shown inphantom) in a right lateral side of the patient's chest. Additionalthoracoscopic trocar sleeves 24 of conventional construction arepositioned within intercostal spaces in the right lateral chest inferiorand superior to access cannula 22, as well as in the right anterior (orventral) portion of the chest. An endoscope 25 of conventionalconstruction is positioned through a percutaneous intercostalpenetration into the patient's chest, usually through one of trocarsleeves 24. The distal end of endoscope 25 (shown in phantom) ispreferably configured to view at an angle between about 30° and 90°relative to the shaft of endoscope 25, to facilitate visualization ofthe heart from the right portion of the thoracic cavity. A light source(not shown) is also provided on endoscope 25 to illuminate the thoraciccavity. A video camera 26 is mounted to the proximal end of endoscope25, and is connected to a video monitor 28 for viewing the interior ofthe thoracic cavity. A first suture organizing ring 30 is mounted to aproximal end of access cannula 22. A second organizing ring 32 ismounted to a support stand 34 fixed to table T. A replacement valve 36is held at the distal end of an introducer 38 between first organizingring 30 and second organizing ring 32. Introducer 38 extends throughsecond organizing ring 32 and is supported by support stand 34.Additional instruments to be used in a procedure such as a retractor 40,as well as cutting, suturing, stapling, aspirating, irrigating and otherdevices, may be introduced through access cannula 22, trocar sleeves 24,and/or small, percutaneous incisions within intercostal spaces of therib cage.

Referring now to FIG. 2, access cannula 22 is positioned within anintercostal space I in the right lateral side of the chest, preferablyin the third, fourth, fifth, or sixth intercostal space between adjacentribs R. Additional trocar sleeves 24A, 24B are positioned withinintercostal spaces superior and inferior to access cannula 22 in theright lateral side of the chest. Access cannula 22 and trocar sleeves24A, 24B are positioned so that instruments 42 introduced through themmay be directed toward the right side of the left atrium of the heart H.A trocar sleeve 24C is positioned in an intercostal space in the rightanterior side of the chest such that endoscope 25 may be introduced toview the thoracic cavity and heart H without interfering withinstruments introduced through access cannula 22 or trocar sleeves 24A,24B. An additional trocar sleeve 24D is positioned in an intercostalspace in the anterior side of the chest just to the right of the sternumand anterior to the right lateral side of the heart H.

It will be understood to those of ordinary skill in the art that, insome cases, it may desirable to eliminate some or all of trocar sleeves24 and/or access cannula 22, and introduce instruments directly throughsmall, percutaneous intercostal incisions in the chest. Advantageously,unlike laparoscopic, arthroscopic, and other endoscopic procedures, nodistension of the chest is required using the method of the invention,so that leakage of distension fluid through percutaneous penetrations isnot of concern. Thus, either thoracoscopic trocar sleeves without fluidseals or percutaneous incisions may be utilized for instrumentintroduction into the thoracic cavity. Trocar sleeves are generallypreferred, however, in order to provide an open passage into thethoracic cavity, to protect adjacent tissue from injury resulting fromcontact with instruments, and to avoid damaging instruments, endoscopes,replacement valves, and the like when introduced into the thoraciccavity.

Referring again to FIG. 2, once access cannula 22 and trocar sleeves 24have been positioned in the patient's chest, endoscope 25 is introducedthrough trocar sleeve 24D and camera 26 is connected to video monitor 28(FIG. 1). Endoscope 25 is manipulated so as to provide a view of theright side of the heart, and particularly, a right side view of the leftatrium. Usually, an endoscope of the type having an articulated distalend, or a distal end disposed at an angle between 30° and 90° will beused, which is commercially available from, for example, Olympus Corp.,Medical Instruments Division, Lake Success, N.Y.

At this point in the procedure, if not previously accomplished, thepatient is placed on cardiopulmonary bypass (CPB), the patient's rightlung is at least partially collapsed, and the patient's heart isarrested. Suitable techniques for arresting cardiac function andestablishing CPB without a thoracotomy are described incommonly-assigned, co-pending applications Ser. No. 07/991,188, filedDec. 15, 1992, and Ser. No. 08/123,411, filed Sep. 17, 1993 (AttorneyDocket No. 14635-4/93002-1), both of which are incorporated herein byreference.

As illustrated in FIG. 3, CPB is established by introducing a venouscannula 70 into a femoral vein 72 in patient P and advancing venouscannula 72 into the inferior vena cava 74 and/or into the interior ofheart H to withdraw deoxygenated blood therefrom. Venous cannula 70 isconnected to a cardiopulmonary bypass system 76 which receives thewithdrawn blood, oxygenates the blood, and returns the oxygenated bloodto an arterial return cannula 78 positioned in a femoral artery 80. Theright lung may also be collapsed at this time and cardiac functionarrested using known techniques. Usually, a tube is introduced throughthe trachea into the right main stem bronchus, and a vacuum is appliedthrough the tube to collapse the lung. Suitable methods for performingthe above procedures may be found in commonly assigned, co-pendingapplication Ser. No. 08/577,547, filed Dec. 22, 1995 (Attorney DocketNo. 14635-002810), the complete disclosure of which has been previouslyincorporated herein by reference.

With cardiopulmonary bypass established, cardiac function arrested, andthe right lung collapsed, the patient is prepared for surgicalintervention within the heart H. Referring again to FIG. 2, a surgicalcutting instrument such as angled scissors 110, as well as a graspinginstrument such as grasping forceps 112, are introduced through accesscannula 22 or through trocar sleeves 24A, 24B. Angled scissors 110 andforceps 112 are used to form an opening in the pericardium, providingaccess to the right side of the left atrium.

FIG. 4A illustrates the view into the thoracic cavity through passage 50of access cannula 22. Angled scissors 110 aided by grasping forceps 112are shown cutting through the right side of left atrium LA to form anatriotomy 162. Atriotomy 162 is formed along dotted line 164 anterior toright pulmonary veins PV. A completed description of techniques forforming such an atriotomy is found in Kirklin and Barratt-Boyes, CardiacSurgery, pp. 329-340, the disclosure of which has been incorporatedherein by reference. Usually, atriotomy 162 will be formed undervisualization by means of endoscope 25 (FIGS. 1 and 2), although directviewing is possible through passage 50 of access cannula 22, or througha trocar sleeve 24.

Upon completion of atriotomy 162, the wall of left atrium LA on theanterior side of atriotomy 162 is retracted anteriorly by means ofthoracoscopic retractor 40, as illustrated in FIG. 1. A variety ofretractors 40 may be used and details on a suitable retractor for usewith the present invention may be found in commonly assigned, co-pendingapplication Ser. No. 08/577,547, filed Dec. 22, 1995 (Attorney DocketNo. 14635-002810), the complete disclosure of which has been previouslyincorporated herein by reference. Retractor 40 is pulled in the anteriordirection to retract the wall of left atrium LA, opening atriotomy 162and exposing the patient's mitral valve MV within the left atrium LA.

Referring to FIG. 4B, retractor 40 is positioned so that tissuesupporting member 500 is oriented with contact surface 502 extendingtowards the atriotomy in the left atrium LA. The surgeon thenmanipulates handle 412 to position tissue supporting member 500 in theatriotomy 162 so that the outer atrium wall AW is on contact surface502. Once tissue supporting member 500 is in the desired position, thesurgeon pulls retractor 40 proximally to retract atrium wall AWanteriorly, as shown in FIG. 4B. Tissue supporting member 500 preferablyextends deeply into the left atrium LA so that the interatrial septum Sis effectively supported on contact surface 502.

At this point, with atriotomy 162 retracted open, the mitral valve MV isexposed for an approach from the right lateral side of the chest viaaccess cannula 22. Instruments may be introduced into the interior ofthe heart H through access cannula 22 or trocar sleeves 24. Theinstruments may extend through the atriotomy 162 to perform a procedurewithin the left atrium LA or may alternatively extend further throughthe mitral valve MV to gain access to the aortic valve in the leftventricle.

Replacement of the mitral valve MV typically comprises cutting orremoval of all or part of the mitral valve leaflets VL. Once the valveleaflets are removed or reduced, it is usually necessary to size thevalve annula VA so as to select a replacement valve 36 of proper sizefor patient P. Various methods and devices may be used for sizing thevalve for replacement. As shown more clearly in FIG. 4B, with thecorrect valve selected, the replacement valve 36 is introduced into theleft atrium and sutured to an annulus at the natural valve position inthe heart. Replacement valve 36 may then be introduced into the leftatrium LA by advancing introducer 38 through passage 50 of accesscannula 22. Replacement valve 36 is oriented on introducer 38 so as tobe introduced edge-first through passage 50. As replacement valve 36 isadvanced into the thoracic cavity, organizing ring 32 maintains tensionon sutures 198, allowing replacement valve 36 to slide along sutures198. Introducer 38 is advanced through atriotomy 162 so that replacementvalve 36 is disposed within left atrium LA. Replacement valve 36 ispositioned against or within valve annulus VA. Square or overhand knotsare then formed in sutures 198 outside of the patient's thoracic cavity,and the knots are pushed by a knot pusher 316 through passage 50 andatriotomy 162 toward sewing ring 228 of replacement valve 36. Suitableprocedures for repair or replacement of the mitral valve may be found incommonly assigned, co-pending application Serial No. 08/577,547, filedDec. 22, 1995 (Attorney Docket No. 14635-002810), the completedisclosure of which has been previously incorporated herein byreference.

After the mitral valve MV has been repaired or replaced, the abovemethod is reversed to remove tissue supporting member 500 from thepatient's thoracic cavity. The atrium wall AW is disengaged from contactsurface 502 and tissue supporting member 500 is removed from theatriotomy. After atriotomy 162 has been closed, any remaininginstruments are removed from the thoracic cavity. A chest tube may beintroduced through one of the trocar sleeves 24 to facilitate evacuationof the pleural cavity. Access cannula 22 and trocar sleeves 24 are thenremoved from the chest wall, and the incisions or penetrations throughwhich they were introduced are closed, usually by suturing or stapling.

The patient's lung may then be reinflated, and cardiac function may berestarted. As described in co-pending application Ser. No. 07/991,188,which has been incorporated herein by reference, infusion ofcardioplegic fluid through aortic occlusion catheter 82 and/orretroperfusion catheter 102 is discontinued, and a saline solution isinfused through one or both of these catheters to irrigate the heart andcoronary arteries (see FIG. 3). The saline solution, along with blood,other fluids, air, thrombus, and other emboli within the heart orcoronary arteries are then aspirated through the inner lumen of aorticocclusion catheter 82, as well as through venous cannula 70 and/orpulmonary venting catheter 79. Occlusion balloon 88 on aortic occlusioncatheter 82 is then deflated, allowing warm, oxygenated blood to flowinto the coronary arteries to perfuse the myocardium. Cardiaccontractions will usually begin soon thereafter. In some cases,electrical defibrillation may be necessary to help restore cardiacfunction. Aortic occlusion catheter 82 and retroperfusion catheter 102may then be removed from the patient. Cardiopulmonary bypass is thendiscontinued, and arterial cannula 78, venous cannula 70, and pulmonaryventing catheter 79 are removed from the patient.

The above description is mainly for illustrative purposes, and othersurgical procedures such as repair and replacement of aortic, tricuspid,or pulmonary valves, repair of atrial and ventricular septal defects, orthe like may be employed with the present invention discussed below.

III. Tool Support Apparatus

Referring now to FIGS. 5-10, a surgical tool support apparatus of thepresent invention for use with a retractor 40, as mentioned above, willnow be described. Although the tissue support apparatus 200 is describedin the context of a mitral valve replacement procedure, it should beunderstood that the surgical tool support apparatus 200 may be used witha variety of other surgical interventional procedures performed in thethoracic cavity. During a typical mitral valve replacement procedure,cardiac tissue in the area of the left atrium may need to be retractedanteriorly to expose the mitral valve for a period of between about30-90 minutes, typically between about 45-60 minutes. During this timeperiod, it is desirable that the retractor 40 pull only in the anteriordirection and not a combination of an anterior and lateral retraction.The position of retractor 40 during the period of anterior retractionshould be maintained in a relatively constant manner so as to braceheart wall and cardiac tissue to provide a clear line of sight andaccess during this surgical procedure. As may occur during the course ofmitral valve replacement, it may become necessary to remove theretractor 40 from the thoracic cavity to perform fluoroscopy or othersurgical procedures which may require unobstructed access to thethoracic cavity or use of the trocar (puncture) occupied by theretractor 40.

Conventionally, retraction of the left atrium LA in an anterior fashionhas been performed by an surgical assistant or scrub nurse whophysically holds the retractor in the desired position for the durationof the valve replacement procedure or a portion thereof. Alternatively,it has been observed that surgeons use clamps or other collar mechanismsto implement a rudimentary locking device to prevent the shaft of theretractor 40 from moving in the distal direction during the operation.The present invention assists the cardiothoracic surgeon by providing anapparatus that replaces rudimentary locking devices used in ajerry-rigged or stop-gap fashion, while providing an easily removableand atraumatic positioning device for the retractor. The presentinvention has a compact configuration that will not further clutter thearea of the surgical procedure. The invention also provides costefficiencies arising from reduced manufacturing and material costsassociated with its compact configuration.

Referring to FIG. 5A, a preferred embodiment of the surgical toolsupport apparatus 200 comprises a base 210 and a clamp assembly 212removably coupled to the base 210 by an L-shaped arm 214 (FIG. 5C). Arm214, of course, may be of other configurations as necessary to properlyposition clamp assembly 212. Alternatively, the assembly 212 may berotatably attached to the base 210 without the use of an arm 214. Asshown, the base 210 typically comprises a rigid plate 215 formed from anon-corrosive, surgically compatible material such as surgical-gradestainless steel (303 stainless steel) or aluminum. The material shouldbe able to withstand autoclaving and other types of sterilizingprocedures so that the tool support apparatus 200 may be cleaned andreused. All parts on the apparatus 200 may also be disassembled tofacilitate sterilization.

As shown more clearly in FIG. 5B-5C, the base 210 has an aperture 216for receiving a shaft of the retractor 40. The aperture 216 facilitatesengagement and alignment of clamps assembly 212 with the shaft of theretractor 40, and it should be understood that the aperture 216 may be acircular or closed path opening in the base or a slit, notch-likeopening extending to an outer edge of the base 210 as shown in FIG. 5A.

Referring to FIGS. 5A-5B, the base 210 of the present invention has anatraumatic tissue-engaging surface 220. The surface 220 may be locateddirectly on rigid plate 215. Preferably, base 210 comprises the rigidplate 215 and a biocompatible elastomeric cushion 222 coupled to theplate. The surface 220 would then be located on the cushion 222. Cushion222 has a cushion aperture 223 (FIG. 5B) corresponding to the aperture216, and the cushion generally mirrors the outline of rigid plate 215.The maximum outer dimension of the tissue-engaging surface 220 ispreferably no more than about 2 inches, more preferably no more thanabout 2.5 inches, and most preferably no more than about 3.5 inches.This maximum outer dimension is in reference to maximum outer diameterfor disc-shaped surfaces or maximum horizontal width for surfaces ofother configurations. The tissue-engaging surface 200 preferably has asurface area of at least about 3 square inches, more preferably at least4 square inches, and most preferably at least 5 square inches. Thetissue-engaging surface 220 of the support apparatus 200 lies on thesurface of the patient's chest so that only the shaft passes into thepatient's chest thereby minimizing trauma to the patient.

The elastomeric cushion 222 may be formed from a variety of materialssuch as 20 durometer silicone, with the understanding that the materialwill not agitate the area of the patient on which the tool supportapparatus 200 rests. Preferably the elastomeric cushion 222 will alsoprovide frictional resistance so as to provide a stable and relativelyslip-resistant grip on the surface of the patient. The elastomericcushion 222 may be integrally formed with the rigid plate 215 of thebase 210, wherein the rigid plate provides structural support while thecushion 222 allows for the typically softer cushion 220. Alternatively,as shown in FIG. 5A, the elastomeric cushion 222 may have a plurality ofprotrusions 224 which frictionally engage a plurality of detents orthrough-holes 226 in the rigid plate of base 210 so that the cushion maybe removably coupled to the rigid plate. It should be understood thatother releasable engagement devices such as velcro or otherdetent/protrusion assemblies may be used to releasably couple thecushion 222 and the rigid plate 215.

In addition to being made preferably of biocompatible and frictional,high-traction material, the atraumatic tissue-engaging surface of thebase 210 also has sufficient surface area so as not to induce a pressuresore or bruise on the patient while the retractor 40 and the toolsupport apparatus 200 are used. In retracting the left atrium LA duringmitral valve MV replacement, the force encountered by the retractor 40is between about 0.5 and 5 pounds, more typically between about 1-3pounds. Pressures between about 0.5-1.0 psi, preferably about 0.98 psi,are desired and considered acceptable to provide atraumatic contactbetween the patient P and the apparatus 200 when a force of 3 pounds isapplied normal to a surface of the patient for approximately one hour.It should be understood that a variety of different sizedtissue-engaging surfaces 220 may be used depending on the amount of timeand force applied during a particular interventional procedure.Referring to FIG. 5A, the area of the tissue-engaging surface 220 of thebase 210 may be altered by using a variety of different sizedelastomeric cushions 222 with the rigid plate 215 of the base 210. Asnoted above, the tissue-engaging surface 220 of the support apparatus200 preferably has a surface area of at least about 3 square inches,more preferably at least 4 square inches, and most preferably at least 5square inches.

In a preferred embodiment, clamp assembly 212, as shown in FIGS. 5A and6A, comprises a first jaw 230 and a second jaw 232. The pair of jaws aretypically opposed to one another and are typically rotatably mounted ona segment 233 of L-shaped arm 214 generally parallel to the base 210.Clamp aperture 235 (FIG. 6D and 6E) and segment 233 act as a rotationallinkage. This rotatability allows the clamp assembly 212 to engage theretractor 40 at a plurality of angles from which the retractor mayextend from the body cavity (FIG. 7B). It should be understood that avariety of other devices known in the art may be used to rotatablycouple the clamp assembly 212 to the arm 214.

Both the first jaw 230 and second jaw 232 have a retractor or toolengaging surface 234. The opposing jaws, in addition to being rotatable,are also axially translatable on the segment 233. A spring 236 such as acoil spring keeps the jaws apart when the clamp assembly is not engagingretractor 40. An axial translation limiter 238 coupled to the clampassembly, such as a set screw, allows slidable axial translation butprevents the complete disengagement of the jaws 230 and 232 from thespring 236. The limiter 238 facilitates alignment between the jaws 230and 232 so that they mate accurately. The spring 236 facilitatesengagement of clamp assembly 212 with the retractor 40 by keeping thejaws apart prior to closing of the clamp assembly. It should beunderstood that a variety of different clamp assemblies may be used solong as the retractor can be releasably engaged and rotate about an axistypically parallel to the rigid plate of the base 210.

A variety of different closure devices may be used to close and engagethe clamp assembly 212 with the retractor 40. FIGS. 5A and 6A show athumb-screw 240 threaded on the horizontal rod or segment 233 (FIG. 5C)of arm 214. Alternatively, a cam-release device 250 as shown in FIGS. 6Band 6C maybe pivotally attached to distal end of generally horizontalsegment of arm 214 to provide closing of the jaws 230 and 232.

As shown more clearly in FIGS. 6C, each jaw 230 and 232 of the clampassembly 212 has a protrusion 252 to facilitate alignment of the jaws230 and 232 when the clamp assembly is closed. Both the protrusions 252are typically machined into the inside, opposing faces of the jaws 230and 232. An exemplary embodiment of jaws of the clamp assembly 212 areshown in FIGS. 6D and 6E. First integrated jaw 254 and second integratedjaw 256 have protrusions 258 and 260 formed with the jaws forfacilitating alignment during closure of the assembly 212. First, outerprotrusions 258 fit over the second, inner protrusions 260 when the jawsare engaged. Second, inner protrusions 260 have a surface 262 whichgenerally conforms with the horizontal, preferably rod-shaped segment233 of the arm 214 to facilitate sliding translation of the second jaw256.

Overtightening surfaces 264 and 266 on the jaws 254 and 256 preventcomplete closure of retractor engagement surfaces 234 which may damagethe retractor 40. Alternatively, retractor engagement surface 234 may becoated with an elastomeric material such as silicone to improvefrictional contact between the retractor and the clamp assembly 212. Thecovering (not shown) may also prevent crimping damage which would likelyresult if the clamp assembly 212 is overtightened on the retractor 40.Holes 268 on surfaces 264 and 266 are provided for engaging the setscrew 238.

Referring now to FIG. 7A, the system 300 for manipulating tissuestructure in the thoracic cavity comprises a retractor 40 and the toolsupport apparatus 200. Once coupled to the apparatus 200, the shaft 39of the retractor 40 acts as a linking member between the contact surface502 on tissue supporting member 500 and the tissue-engaging surface 220.The surfaces 220 and 502 act like a clamp to reposition tissue in a bodycavity while pressing against typically a outer surface of the patientor body cavity. Clamp assembly 212 on the apparatus 200 is used tosecure the apparatus 220 to the retractor 40. It should be understoodthat although in the preferred embodiment the tool support apparatus 200is removably coupled to the retractor 40, alternate embodiments of thesystem 300 may comprise a retractor 40 that may be slidably butundetachably coupled to the support apparatus 200.

Referring to FIG. 7B, the ability to rotate the clamp assembly 212 onsegment 233 (FIGS. 5A and 5C) allows the apparatus 200 to engage shaft39 of the retractor 40 when the shaft does not exit a body cavity, suchas the thoracic cavity TC, at a normal angle. This aspect of the presentinvention allows support apparatus 200 to position the tissue supportmember 500 at a variety of angles to best provide access and line ofsight to the area of surgical intervention.

A method for manipulating tissue structure using system 300 will now bedescribed with reference to FIGS. 8-10. The method comprises introducinga tissue positioning tool such as the retractor 40 having shaft 39 (FIG.7A) within the thoracic cavity through a percutaneous penetration. Thetool or retractor 40 may be assembled within the thoracic cavity TC asshown in FIG. 8. The tool may also be introduced through trocar 24 oralternatively through a percutaneous puncture without the trocar (FIG.9). In certain scenarios, it is necessary to introduce individualportions of the tissue positioning tool 40 through first and secondpercutaneous penetrations in the thoracic cavity. FIG. 8 shows theretractor 40 inserted through trocar 24 while tissue supporting member500 is inserted through trocar 22. The distal tip 41 of the retractor 40may be threaded or otherwise adapted to be releasably coupled to thetissue supporting member 500. The retractor 40 is coupled to the member500 and is now ready to engage the tissue surface (FIG. 9). It should benoted that the tool support apparatus 200 may be connected to shaft 39of the retractor 40 either prior to inserting the retractor 40 into thetrocar 24 or anytime thereafter.

With the tool or retractor 40 ready to engage the tissue structure suchas the atrium wall AW of the left atrium LA, force is applied to theshaft of the tissue positioning tool to retract the tissue structure.FIG. 9 shows the system 300 where the tissue supporting member 500 andthe retractor 40 have been introduced into the thoracic cavity andpositioned to maintain a force against the tissue structure of thepatient's heart. This force, typically between about 1-3 lbs, providesretraction that opens the line of sight and access to the mitral valveMV. Once the tool or retractor 40 is in position, the tool supportapparatus 200 may be positioned or repositioned along the shaft 39.Adjustments are then made to engage or close the clamp assembly 212 onthe support apparatus 200 with the shaft 39. This may involve tighteninga thumb-screw, pulling on a release lever, or using other known methodsof closure. By pressing against a surface of the patient such as theouter surface of the chest, the apparatus 200 can position the retractor40 and maintain the retractive force on the retractor as required toprovide line of sight and open access to the mitral valve MV. FIG. 9shows an optional aspect of the method where the trocar 24 is not usedwith the retractor 40 through the percutaneous intercostal penetration.FIG. 10 provides an alternate view of the apparatus 200 engaged to theretractor 40 and resting on the chest of a patient. Although thedrawings show the retractor 40 positioned at an angle normal to thesurface of the patient, it should be understood that the apparatus 200can engage and position the retractor 40 at a variety of other differentangles.

Referring now to FIGS. 11A and 11B, alterative embodiments of the toolsupport apparatus 200 will be described. In FIG. 11A, the firstalternate support apparatus 600 comprises of a first alternate base 602having an aperture 603 and a carriage 604 for rotatably supporting anengagement assembly 606 to base 602. A shaft (not shown) extendingbetween the carriage 604 has a user interface 608 that providesrotational positioning for the engagement clamp assembly 606. A setscrew 610 provides frictional engagement with a retractor 40.

FIG. 11B illustrates a second alternate support apparatus 650 which hasa second alternate base 652 having an aperture 654. The base 652 isremovably coupled to an engagement assembly 656 which is removablycoupled to base 652. The base has a tongue 657 for releasably engaginggroove 658 on engagement assembly 656. Engagement assembly 656 has anengagement surface 659 which is rotatable about an axis horizontallyparallel to the base 652. A screw-type tightening device 660 can be usedto engage a second, opposing engagement surface (not shown) againstengagement surface 659 to hold a retractor 40 therebetween. Theapparatus of the present invention may have a variety of differentembodiments so long as the apparatus has a base of sufficient surfacearea to prevent trauma to the patient, an aperture or open space foraccommodating the retractor 40, and a clamp assembly that can engage atool and rotate about an axis generally horizontal to the base.

A tool support apparatus 200 according to the present invention may bepackaged together with instructions for use (IFU) in a kit as shown inFIG. 12. A conventional package, which may be a pouch 700 or any othersuitable package, such as a tray, box, tube, or the like, may be used tocontain the apparatus 200 and IFU 710, where the IFU may be printed on aseparate sheet and/or may be printed on the packaging itself. The kitmay also include a retractor 40 which may be permanently or releasablycoupled to the apparatus 200. Optionally, but not necessarily, the toolsupport apparatus 200 and/or the retractor 40 may be sterilized withinthe package, e.g. by radiation or ethyleneoxide. The instructions willset forth any of the aspects of the method of the present inventiondescribed above.

Although the foregoing invention has been described in some detail byway of illustration and example, for purposes of clarity ofunderstanding, it will be obvious that certain changes and modificationsmay be practiced within the scope of the appended claims.

What is claimed is:
 1. A method for manipulating a tissue structurewithin a thoracic cavity of a patient, comprising the steps of:providinga tissue positioning tool having a shaft, a tool support apparatus, anda tissue supporting member, the tool support apparatus having a clampassembly configured to secure the shaft to the tool support apparatus,the tool support apparatus also having a base, the clamp assembly beingpivotable relative to the base; positioning the tool support apparatuson an outer surface of a patient's chest; introducing the tissuesupporting member into the patient's thoracic cavity; contacting atissue structure in the thoracic cavity with the tissue supportingmember, the tissue supporting member being coupled to the shaft;applying a force to the shaft so that the tissue supporting member movesthe tissue structure to a displaced position; and locking the shaft tothe tool support apparatus with the clamp assembly after the applyingstep so that the tissue structure maintains the displaced position. 2.The method of claim 1, wherein the providing step is carried out withthe clamp assembly having an actuator, the actuator being movable to alocked position which secures the shaft relative to the tool supportapparatus, the actuator also fixing an angular orientation of the clampassembly relative to the base when moved to the locked position therebypreventing pivoting of the clamp assembly relative to the base.
 3. Themethod of claim 1, wherein the locking, applying, contacting,introducing and positioning steps are carried out with only the shaftpenetrating the patient's chest and the tool support apparatus engagingonly the outer surface of the patient's chest.
 4. The method of claim 1,wherein the providing step is carried out with the tool supportapparatus having a base, the base having a bottom surface having asurface area of at least 3 square inches.
 5. The method of claim 1,wherein:the providing step is carried out with the tool supportapparatus having an elastomeric cushion; and the positioning step iscarried out with the elastomeric cushion engaging the outer surface ofthe patient's chest.
 6. A method for manipulating a tissue structurewithin a thoracic cavity of a patient, comprising the steps of:providinga tissue positioning tool having a shaft, a tool support apparatus, anda tissue supporting member, the tool support apparatus having a clampassembly configured to secure the shaft to the tool support apparatus;positioning the tool support apparatus on an outer surface of apatient's chest; introducing the tissue supporting member into thepatient's thoracic cavity; contacting a tissue structure in the thoraciccavity with the tissue supporting member, the tissue supporting memberbeing coupled to the shaft; applying a force to the shaft so that thetissue supporting member moves the tissue structure to a displacedposition; and locking the shaft to the tool support apparatus with theclamp assembly after the applying step so that the tissue structuremaintains the displaced position; the introducing step being carried outwith the tissue supporting member passing through a first opening in thepatient's chest; and the applying step being carried out with the shaftpassing through a second opening in the patient's chest.
 7. The methodof claim 6, wherein the providing step is carried out with the toolsupport apparatus having a base, the clamp assembly being pivotablerelative to the base.
 8. The method of claim 6, further comprising thestep of:attaching the tissue supporting member to the shaft within thepatient's chest.
 9. A method for manipulating a tissue structure withina thoracic cavity of a patient, comprising the steps of:providing atissue positioning tool having a shaft, a tool support apparatus, and atissue supporting member, the tool support apparatus having a clampassembly configured to secure the shaft to the tool support apparatus,the tool support apparatus also having a base, the base having a bottomsurface having a surface area of at least 3 square inches and a maximumouter dimension of no more than 3.5 inches; positioning the tool supportapparatus on an outer surface of a patient's chest; introducing thetissue supporting member into the patient's thoracic cavity; contactinga tissue structure in the thoracic cavity with the tissue supportingmember, the tissue supporting member being coupled to the shaft;applying a force to the shaft so that the tissue supporting member movesthe tissue structure to a displaced position; and locking the shaft tothe tool support apparatus with the clamp assembly after the applyingstep so that the tissue structure maintains the displaced position. 10.The method of claim 9, wherein the providing step is carried out withthe bottom surface having a circular shape with a radial slot.
 11. Amethod of retracting a tissue structure, comprising the stepsof:providing a tissue positioning tool having a shaft and a tissuesupporting member; introducing the tissue supporting member into thepatient through a first penetration in the patient; introducing theshaft through a second penetration in the patient; attaching the tissuesupporting member to the shaft within the patient; contacting a tissuestructure in the patient with the tissue supporting member; and applyinga force to the shaft so that the tissue supporting member moves thetissue structure to a displaced position.
 12. The method of claim 11,wherein the providing step is carried out with the tissue positioningtool including a tool support apparatus.
 13. The method of claim 12,further comprising the steps of:positioning the tool support apparatuson an outer surface of a patient's chest; and locking the shaft to thetool support apparatus after the applying step so that the tissuestructure maintains the displaced position.